Auxiliary Power Systems

Our know-how at the heart of auxiliaries

Wabtec has developed a set of proven power modules that enable Transit providers to meet the numerous technical challenges of integrating and maintaining an auxiliary power system. Our solutions help reduce time to market without compromising flexibility.

Today’s trains are equipped with an increasing number of electrical auxiliaries to boost thermal comfort, ensure good indoor air quality, and more. Auxiliary power systems provide the constant, regulated power needed to power these auxiliaries. However, supply voltage dips, electromagnetic interference, complex assembly integration, and reduced reliability can all compromise the effective operation of on-board auxiliary power systems.  

Regulating external factors  

Auxiliary power systems are essential to powering auxiliaries on trains. But a variety of external factors can impact auxiliary power performance. For example, electromagnetic interference from the overhead contact line can disturb frequencies, resulting in malfunctions in the signaling circuit. In addition, when integrating large components into the train design, finding a place for the auxiliary power system can be a challenge. And a weak auxiliary power supply can reduce reliability, resulting in lower train availability and higher maintenance costs. Meeting these challenges requires a partner with comprehensive auxiliary power know-how to design the right solution for your needs.   

Powering today’s trains  

Wabtec provides industry-leading power electronics that are used on board all types of mass transit vehicles: light-rail, high-speed, main-line, and underground trains, trams, and trolley buses. Compatible with a variety of tensions (i.e., overhead line voltage, third rail), our power electronics can convert input voltages up to 3,000 volts. They also have an output power range from 10 to 100 KVA.  

Our product portfolio includes the following:

  • Auxiliary converters: Our converters meet all of your vehicle’s power conversion needs by switching the input voltage from the overhead line or third-rail power supply into constant, regulated power. They can supply power to a variety of loads, such as air conditioning and ventilation systems, air generation and treatment units, and more.  
  • Battery chargers: Our chargers conveniently charge your auxiliary batteries, supply power to electronic equipment, and operate lighting during train operation. 

Positive energy savings  

Auxiliary power systems do more than just supply power to loads, they can also help trains realize major energy savings. Our new business model helps Transit providers reach an optimized energy-efficiency level by achieving shared energy-saving performance targets. Our range of innovative technical solutions are designed to help you select and implement a chosen configuration, while adapting to your operational constraints.  

Auxiliary power innovator  

Wabtec is an international manufacturer and supplier of on-board railway equipment and systems. Since 1979, we have provided power electronics and auxiliary power systems to train manufacturers and operators.  

We developed our first auxiliary converter in 1979. Since then, we have been at the forefront of innovation, developing auxiliary power systems with ever-higher reliability and efficiency. In 2004, we launched our breakthrough patented Katium® technology, going on to develop a simplified topology in 2011 and the Katium® SiC in 2017.


By choosing Wabtec, you benefit from

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Dual expertise

that can address your technical needs in both power electronics and auxiliary systems

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All-in-one auxiliary systems

in which auxiliary and inverter are one—that target the major challenges of traditional auxiliary power systems

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Energy savings

Our technical expertise in and commitment to energy savings, both of which help you to achieve your targets in energy efficiency

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Gobal presence with local solutions

including competence centers, manufacturing plants, and engineering support sites for converters in France, Canada, the Czech Republic, and the United States, as well as Wabtec manufacturing facilities in more than 30 countries


Proven power modules for every need

  • Interfacing
  • Optimization
  • Performance

State-of-the-art interfacing

Katium® is a unique and smart power topology that reduces the weight and volume of power converters. You benefit from the following:

Increased resistance to supply voltage dips

Iced or electric arcs can produce voltage dips. Katium®’s topology acts as a current source and can run without interruption, even in the most challenging conditions.

Greater flexibility during supply voltage surges

The power-grid voltage can sometimes exceed specifications. Katium®’s adaptive, multi-cell topology withstands any surge duration by providing a broad input voltage range.

Advanced digital filtering of electromagnetic interference

To ensure the safe operation of track signaling, Katium® operates as a digital-input filter that can adjust its input impedance and reject load interference.

System optimization

Wabtec products and solutions are designed to meet your complex mechanical specifications, overcome design challenges, increase energy efficiency, and optimize load control.

Complex assembly integration

Thanks to its light weight and small size, Katium® can be perfectly adapted to the unique mechanical specifications of your auxiliary power system.

Standard design limitation

Whether you need to facilitate integration, increase efficiency, or preserve availability, we can provide the most adapted solution (i.e., 3+1 phase inverter, dedicated HVAC inverter, distributed system).

Optimizing auxiliary

Our wide range of products offers compact and energy-efficient solutions that enable you to take full control of your auxiliary system.

Performance enhancement

Our products and solutions focus on enhancing the performance of your auxiliary power system via high-performance technologies, powerful monitoring tools, and designs that improve reliability.

Cooling in a confined space

Our auxiliary power system uses silicon carbide (SiC) power switches that can operate at higher temperatures and have lower switching losses.

Reducing repair time

Our solutions can quickly identify the fault module through built-in self-diagnosis. Weighing less than 15 kg, they are lightweight and can be replaced quickly.

Ensuring optimal reliability

To incorporate reliability into the design, we include complete environmental characterization. We also consider feedback from our +15,000 in-service systems and focus on continuous improvement.

Success Stories

Leading Innovation Since 1979

Belgium – Converter of choice for new M7 platform

Bombardier’s M7 carriages have been in use in Belgium since September 2018, bringing passengers greater comfort and safety. Faiveley Transport’s strong relationship with SNCB and our partnership approach to solving technical issues led us to be chosen to provide auxiliary converters for 355 carriages with an option for 710. The M7 design is an evolution of the M6 and presented specific challenges. Bombardier required a lighter, more powerful auxiliary converter that: 1) could be integrated into the carriage design; 2) controls harmonic current, minimizing disruption to signaling; 3) is compatible with cateners in Belgium and the Netherlands; and 4) has onboard functions comparable to those of the current M6. Faiveley Transport’s solution checked all these boxes while increasing reliability.

New York - Product qualification for R160

Katium® technology is approved for use on the New York metro following retrofit as a demo on two R160 trains for a year. It addresses specific operator demands for a converter offering superior performance without exceeding existing volumes. Our Katium® solution is quieter and more energy efficient than converters currently used on the R160. Faiveley Transport teams also worked on mechanical integration to identify a solution that makes it easier for maintenance engineers to access and maintain the technology.

Auxiliary power supply Case Study 2
SINGAPORE - Energy savings for SMRT

Our converter solution for the Singapore metro helped the client achieve its objective to save energy. The new units are up to two-thirds more efficient than the previous generation, with energy savings achieved through improved HVAC efficiency. Other features of our solution helped the client optimize costs. For example, the use of natural convection and no filters reduces maintenance. In addition, the use of several smaller converters for each carriage achieves optimum weight distribution without impacting carriage design.

Contact Us

Wabtec Transit Rail


Faiveley Transport Tours

+33 (0)2 47 32 55 55

ZI Bois de Plante - Rue Amélia Earhart
BP 43 - 37700 La Ville-aux-Dames - France


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If you prefer to contact us directly, email info [dot] aps [at] wabtec [dot] com (info[dot]aps[at]wabtec[dot]com)